1. Field of the Invention
The present invention relates to a sound processing apparatus, a sound image localization method, and a sound image localization program, which are adapted to an apparatus for reproducing sound signals, such as a television receiver or an on-vehicle audio apparatus, and move a sound image originated from a sound to be reproduced.
2. Description of the Related Art
Recent television receivers and on-vehicle audio apparatuses are mostly designed to have a speaker located below the head of a listener. When reproduced sounds are generated from a speaker located below the head of a listener, therefore, a sound image is expanded below the head of the listener, giving unnatural sound field feeling.
To improve such a situation, therefore, it is desirable to provide a function of raising the localization position of a sound image to give natural sound field feeling. In the past, a process of emphasizing a frequency band component (around 8 kHz) at which a listener feels the direction of a sound source above the head in terms of the auditory sensation is carried out as disclosed in, for example, JP-UM-A-5-43700 (Patent Literature 1).
A frequency band where a specific directivity is sensed depending on the center frequency of stimulation regardless of the direction of a sound source is defined as a directional band by Blauert. The definition is mentioned in, for example, Blauert, J. (1969/70) “Sound localization in the median plane” Acustica 22, 205-213 (Non-patent Literature 1).